Accelerator-Based Production of Scandium Radioisotopes for Applications in Prostate Cancer: Toward Building a Pipeline for Rapid Development of Novel Theranostics

In the field of nuclear medicine, the β(+) -emitting (43)Sc and β(−) -emitting (47)Sc are promising candidates in cancer diagnosis and targeted radionuclide therapy (TRT) due to their favorable decay schema and shared pharmacokinetics as a true theranostic pair. Additionally, scandium is a group-3 transition metal (like (177)Lu) and exhibits affinity for DOTA-based chelators, which have been studied in depth, making the barrier to implementation lower for (43/47)Sc than for other proposed true theranostics. Before (43/47)Sc can see widespread pre-clinical evaluation, however, an accessible production methodology must be established and each isotope’s radiolabeling and animal imaging capabilities studied with a widely utilized tracer. As such, a simple means of converting an 18 MeV biomedical cyclotron to support solid targets and produce (43)Sc via the (42)Ca(d,n)(43)Sc reaction has been devised, exhibiting reasonable yields. The (Nat)Ti(γ,p)(47)Sc reaction is also investigated along with the successful implementation of chemical separation and purification methods for (43/47)Sc. The conjugation of (43/47)Sc with PSMA-617 at specific activities of up to 8.94 MBq/nmol and the subsequent imaging of LNCaP-ENZaR tumor xenografts in mouse models with both (43/47)Sc-PSMA-617 are also presented.